This question is a hard one to answer when the firearm in question is not spelled out in the script. Having worked in both TV and movies, the use of firearms is sometimes a secondary issue, the true brand, caliber, type, etc is not germane to the story line (in the minds of script writers, who sometimes never take the time to do their research), it’s just a gun. Of course in this series the handgun in question is a GI issue .45 acp 1911 A1. It is generally considered the military used over a half a dozen manufacturers to produce the handguns used by our troops. By Vietnam, an issue 1911, would have been rebuilt several times so the frame, slide, barrel and most components would have been replaced several times so most guns would be a true hybrid, given that, it would be hard to say what manufacturer produced the pistol unless the gun was in the “family” since it original issue (which did happened).
As far as the 9mm issue, most .45’s used as props at the time were 9mm as the theatrical guns functioned best with those blanks. As far as “blanks” the Industry uses several different types, including the famous 5-in-1 blank and others but that’s a discussion for another thread.